Insulated squirrel-cage winding



A. KIMBLE.

INSULATED SQUIRREL CAGE WINDING. APPLICATION FILED uAY12.1919.

1,375,007. I i PatenfedApr.19,1921.

UNITED STATES PATENT OFFICE.

AUSTIN KIMBLE, OF WAUSAU, WISCONSIN, ASSIGNOR TO MARATHON ELECTRIC MFG.

COMPANY, OF WAUSAU, WISCONSIN, A CORPORATION OF WISCONSIN.

INSULATED SQU'IRREL-CAGE WINDING.

Specification of Letters Patent. I

Patented 'Apr. 19, 1921.

Application filed May 12, 1919. Serial No. 296,648.

To all whom it may concern:

Be it known that I, AUSTIN KIMBLn, a

' citizen of the United States of America, and

a resident of Wausau, county of Marathon, and State of Wisconsin, haveinvented certain new and useful lmp'rovements in Insulated Squirrel-CageWindings, of which the following is a specification.

This invention relates to squirrel cage windings, and rotor' structuresand methods of forming same. The main objects of the invention are toprovide a squirrel cage rotor of simplified and more unitary character;to provide a simplified and better form of squirrel cage winding; toprovide im-' proved means for insulating a squirrel cage winding fromthe core; to provide such a device adapted for eflicient ventilation; toprovide a squirrel cage in place on the core in integral electrodepositform; and to provide a method for forming and insulating a squirrel cagewinding such as specified.

An illustrative embodiment of this invention is shown in theaccompanying drawings, in which Figure 1 is an end view part1 insection, substantially onthe line 11 0 Fig. 2.

Fig. 2 is a longitudinal section on the line 22 of Fig. 1.

Fig. 3 is an enlarged sectional detail of one of the insulated bars inplace in its slot.

Fig. 4.- is an enlarged section across one of the core slots after thewax and black lead have been applied and preceding the electrodepositstep of the process.

In theconstruction shown in the drawings, the rotor 1 comprises alaminated core 2 mounted securely on the shaft 3 in any of the numerousapproved ways understood in the art. Said core is provided with asquirrel cage, including a peripheral series of bars 4 disposed in coreopenings or slots 5, and having their corresponding ends joined by rings6. The squirrel cage is insulated from the core by a layer 7 of suitabledielectric material, preferably japan, which is adapted for readyapplication in accordance with the scribed.

The method of forming the rotor specified is as follows: The assembledslotted core 2 is first coated with wax as shown at 8, so as to protectthe same from any electrodeposit of copper directly thereon. The wax isapprocess hereinafter deplied by rolling the core in hot wax. Powderedconducting material, such for instance as black lead shown at 9, is thenapplied to such parts of the core as are to receive the electrodepositwhich is to form the squirrelcage, for which purpose it may be blown onwith an air brush. The black lead is apphed to thelnterior of the slots5, and to the peripheral zones 10 on the ends of the core connectingsaid slots, so that when the core is placed in the plating bath and theelectrolytic process is started, copper will be deposited as an integrallayer, 4 and 6, lining the slots 5 and covering said end zones 10,whereby an integral hollow bar squirrel cage winding is formed in placeon the core.

The core slots 5 are so formed that when a suflicient thickness ofcopper has been deposited (say 1/16), there will remain a centralopening 11 in each .bar 4 adapted to enhance ventilation.

After the squirrel cage 4, 6 is formed, the rotor is heated and the wax8i-s blown out or otherwise removed, after which the core is placed in areceptacle containing japan which replaces the wax, permeating all theinterstices between the core and the electrodeposit. The core is thenbaked sufficiently to dry and harden the japan 7, whereupon as a resultof said process the squirrel cage is thoroughly insulated from the coreand is held rigidly in place.

Although but one specific embodiment of this invention is herein shownand described, it is to beunderstood that numerous details of theconstruction and process set forthmay be altered or omitted withoutdeparting from the spirit of this invention as defined by the followingclaims.

I claim:

1. The method of forming a squirrel cage form of dynamo-electric device,which consists in coating a magnetic core with wax,

sists in coating a magnetic core with Wax, finally applying japanbetween the core and then applying a coating of conducting mate' theelectrodeposit in place of thewax rerial to the core over areas to beoccupied by moved. 10 the end rings and bars of the squirrel cage,Signed at Chicago this 9th day of May then applying an electrodeposit ofconduct- 1919. ing metal to the coated areas, then heatin the platedcore and removing the Wax, ana AUSTIN KIMBLE.

